1. Field of the Invention
This invention generally relates to an input/output device for inputting and outputting information to and from an associated apparatus, and more in particular, to an integrated input/output device suitable for use in such an apparatus as a facsimile machine as an integrated reading/recording unit.
2. Description of the Prior Art
An apparatus, such as a facsimile machine, is typically provided with an input device for inputting information and an output device for outputting information. In the case of a facsimile machine, such an input device includes a reading unit for optically reading an original document for converting visual image information into electrical image information, and such an output device includes a recording unit for recording image information on recording paper.
Typical prior art input and output devices are illustrated in FIGS. 4 and 5a and 5b. FIG. 4 schematically shows a prior art facsimile machine which is provided with an input device serving as a reading unit and an output device serving as a recording unit separately. In the structure shown in FIG. 4, the right-hand half defines an input device, which functions as a reading unit, and the left-hand half defines an output device, which functions as a recording unit. As shown, the input device includes a light source 31 for emitting light toward an original document 32 which moves, for example, from left to right in the plane of FIG. 4. The input device also includes a reflecting mirror 33 for reflecting the light from the original document toward an image sensor 35, such as a CCD image sensor, through a focusing lens 34. Also provided in the input device is a sensor driver 36 which is operatively associated with the image sensor 35. As well known in the art, the image sensor 35 is typically comprised of a plurality of photoelectric elements arranged in the form of a single array whose longitudinal direction is normal to the direction of movement of the original document 32. Thus, as the original document 32 moves from left to right, the image information on the original document 32 is optically read line by line by the image sensor 35.
As set forth above, the left-hand half of the structure shown in FIG. 4 defines an output device, which serves as a recording unit, and it includes a roll of recording paper 37, a thermal printhead 38 for recording data on the recording paper 37, and a head driver 39 which is operatively associated with the thermal printhead 38. Thus, image information to be recorded is supplied from the driver 39 to the thermal printhead 38 so that image information is recorded on the recording paper 37. In the structure of FIG. 4, since the input and output devices, serving as reading and recording units, respectively, are provided separately, they occupy a significant amount of space within a machine housing, and, thus, there is a difficulty in making the entire apparatus compact in size. In addition, each of the input and output devices is comprised of various discrete elements, so that it requires alignment among elements and a care in assembling.
FIGS. 5a and 5b illustrate an input device which may serve as a reading unit for use in a facsimile machine. The input device shown in FIGS. 5a and 5b defines a reading unit having no focusing element, such as a lens. That is, this input device includes an LED array 41 as a light source. The input device of FIG. 5 also includes a glass substrate 43 on the bottom surface of which a common electrode 44 is formed. An amorphous silicon film 45 is formed on the common electrode 44, and a transparent electrically conductive film 46 is formed on the amorphous silicon film 45. A metal film 47 is also formed on the transparent electrically conductive film 46. It should be noted that the transparent electrically conductive film 46, together with the overlying metal film 47, is, in fact, divided into strips as spaced apart from each other at a predetermined pitch to define an array of individual electrodes 50. As a result, those portions of the amorphous silicon film 45 which are sandwiched between the common electrode 44 and the individual electrodes 50 define an array of photoelectric elements. A light guiding window 42 is formed at the tip end of each of the individual electrodes 50. A transparent protective film 48 is formed to cover the entire bottom structure of the substrate 43.
With this structure, an original document 49 to be read is moved, for example, from left to right while being kept in contact with the protective film 48. Light emitted from the LED array 41 passes through the windows 42 and impinges on the original document 49, and the light reflecting from the original document 49 is received by the array of photoelectric elements defined in the amorphous silicon film 45 between the common electrode 44 and the individual electrodes 50. The input device shown in FIGS. 5a and 5b is smaller than the input device shown in FIG. 4; however, since it is only an input device, there must be provided a separate output device.